Drain plug and float release for carburetor bowls



April 14, 1959 R. G. HENNEMANN 2,331,791

DRAIN PLUG AND FLOAT RELEASE FOR CARBURETOR BOWLS Filed Aug. 50, 1957 FIG.|.

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INVENTOR. RAYMOND G. HENNEMANN ATTORNEY United States Pa DRAIN PLUG AND FLOAT RELEASE FOR CARBURETOR BOWLS Raymond G. Hennemann, St. Louis, Mo., assignor to ACF Industries, Incorporated, New York, N.Y., a corporation of New Jersey Application August 30, 1957, Serial No. 681,236

2 Claims. (Cl. 137-409) This invention relates to carburetors for small internal combustion engines of the type commonly employed for driving lawn mowers, chain saws, and electric generators, and is more particularly concerned with the provision of a combined drain plug and float release unit for carburetor fuel bowls.

When engine driven devices have been out of use for several days, any fuel remaining in the bowl, after such use, evaporates and leaves a gummy deposit which must be removed prior to using the device to insure satisfactory operation of the carburetor, as the gum tends to clog the fuel passages in the carburetor and sometimes causes the float to become attached to the bowl. To prevent a formation of gummy deposits in the fuel bowl, the fuel should be drained from the bowl if the device is not to be operated for several days.

An object of the present invention is to provide means adapted to facilitate drainage of fuel from a carburetor bowl, and also adapted to release a float if the latter should become attached to the bowl by a gummy deposit therein.

Another object of the invention is to provide a combined drain plug and float release unit which is relatively simple and inexpensive to manufacture and easy to install on a carburetor fuel bowl.

A further object of the invention is to mount a combined drain plug and float release unit on a resilient support member clamped between the fuel bowl and a boss or post depending from the carburetor body by means of a fuel bowl mounting screw.

The invention embodies other novel features, details of construction, and arrangement of parts which are hereinafter set forth in the specification and claims, and illustrated in the accompanying drawings, wherein:

Fig. 1 is a longitudinal sectional view of a conventional carburetor provided with a combined drain plug and float release unit embodying features of the invention.

Fig. 2 is an enlarged detail top plan view of the combined drain plug and float release unit.

Fig. 3 is a side elevation of same.

Fig. 4 is a sectional view taken along the line 4-4 of Fig. 2.

Fig. 5 is a disassembled side view of the novel drain valve.

Referring now to the drawings for a better understanding of the invention, a conventional carburetor is shown as comprising body 6 having a mixture conduit 7 provided with a choke valve 8 and a throttle valve 9. A venturi 11 is provided in the mixture conduit between the choke and throttle valves.

The body 6 is formed with a depending tubular stem 12 which is internally threaded to receive a cap screw 13. An annular groove 14 is formed in the body to receive the rim portion of a cup-shaped fuel bowl 16 which is formed with an aperture to receive the shank of the screw 13.

The bowl is provided with a fuel inlet, having a needle valve therein, to be actuated by a float 17 supported for 2,881,791 1C6 Patented Apr. 14, 1959 pivotal movement relative to the bowl to maintain a substantially constant fuel level therein.

A main fuel nozzle 18 is fixed within-the tubular stem 12 and formed with a fuel metering orifice 19 for the passage of fuel from the fuel bowl 16 to the mixture conduit 7. A hollow fuel metering rod 21 is adjustably mounted on the body 6 to regulate the flow of fuel through the orifice 19, the rod also forming part of an idle fuel passage 22 leading to idle port 23.

Fuel bowl 16 is provided with a combined drain plug and float release unit 26 comprising a blank of resilient sheet metal formed with an arcuate slot 28 to define a base portion 29 and an arcuate spring portion 31 offset from the plane of the base portion. The base portion 29 is received between the post 12 and the bottom of bowl 16 and is formed with an aperture 32 to receive the shank of the cap screw 13.

The fuel bowl is provided with a drain opening 33, the edge of which forms an annular valve seat 34. A valve member 35 has face ring 36, preferably of synthetic rubber, abutting head disk 37. Valve face 36 is normally urged into engagement with seat 34 by spring portion 31. A stem 38 depends from valve head 37 through drain hole 33 and may be manually engaged to lift the valve member away from the seat 34 to drain the fuel from the bowl. The valve member has an upward extension 39 which serves as a stop to prevent the float from dropping to the bottom of the bowl, as indicated in broken lines in Fig. 1. In case the float should, nevertheless, become stuck in gummy deposit in the bowl, stem 38 may be pushed upwardly to free the float.

Certain structures have been described herein which will fulfill all the objects of the present invention, but it is contemplated that other modifications will be obvious to those skilled in the art which come within the scope of the invention as defined by the appended claims.

I claim:

1. In a carburetor for an internal combustion engine having a float bowl, a hinged float in said bowl for controlling a needle valve at the inlet to said bowl, a fuel drain opening formed in the bottom of said bowl, a part attached to the inside of said fuel bowl, a resilient extension on said part having an end portion forming a flexible valve support, a valve assembly on the end portion of said flexible valve support including a valve and stem, said valve being normally biased by said resilient extension into engagement with the inside of said bowl at said drain opening for closing the latter, said stem projecting outwardly through said drain opening and also inwardly of said valve for engagement with said float when the latter is in its lowermost position, said outwardly projecting part of said stem forming a manually operable button, which, when forced within said fuel bowl against the tension of said resilient extension, opens said valve means to drain the fuel from said fuel bowl and lifts said float when the latter is in its lowermost position.

2. In a carburetor for internal combustion engines, a carburetor body having a hollow internally threaded stem, a cup-shaped fuel bowl having its rim portion in sealing engagement with the body and its central portion apertured for surrounding said stem, means threadedly engaging with said stem for closing the aperture in said fuel bowl and for securing said bowl in sealed engagement with said carburetor body, a hinged float for operating an inlet valve for said fuel bowl, a drain opening in the bottom of said fuel bowl, and a combined drain plug and float release unit comprising; an apertured part surrounding said stem and secured in place between said threaded means and the inside of said bowl, a flexible extension on said apertured part, a valve on said flexible extension biased thereby into normal closing relation with said. drain opening, a stem am "said flexible extension pro- References Cited" in the-file cf'tfiis patent jecting outwardly through said drain opening and inward- ISIALTES PATENTS 1y thereof into engagement with said float when in its lowermost positing, said stein forming a manually ope r- 1 *"i 122 5 ated buttcm extenol? of saadfuel bowl in; mov-mg send 5 2,790:458 Kale" p 1957 valve ofi its seat to drain the bowl, and for simultaneously lifting said float. 

